Which metal is used in radiation shielding?

During a $\beta$-decay,the mass of the atomic nucleus

Which of the following statements is not true for radioactive decay?

The number of $\beta$-particles emitted in the radioactive decay process $_{92}U^{238} \to _{82}Pb^{206} + x(_{2}He^{4}) + y(_{-1}e^{0})$ is:

$A$ radium $_{88}Ra^{224}$ isotope,on emission of an $\alpha$-particle,gives rise to a new element whose mass number and atomic number will be:

In the decay sequence:
$^{238}_{92}U$ $\xrightarrow{- x_1} ^{234}_{90}Th$ $\xrightarrow{- x_2} ^{234}_{91}Pa$ $\xrightarrow{- x_3} ^{234}_{92}Z$ $\xrightarrow{- x_4} ^{230}_{90}Th$
$x_1, x_2, x_3$ and $x_4$ are particles/radiation emitted by the respective isotopes. The correct option$(s)$ is/are-
$(1)$ $Z$ is an isotope of uranium
$(2)$ $x_2$ is $\beta^{-}$
$(3)$ $x_1$ will deflect towards negatively charged plate
$(4)$ $x_3$ is $\gamma$-ray